CONSTRUCTION: THE MOULDS, THE GUARANTEE OF RIGID COMPOSITE PARTS

Interview with Laurent FortinonB5 Moulding Manager

We asked Laurent Fortinon, the workshop manager, who is responsible for ensuring the smooth running of the SEVENTY 7 moulding operation, to explain this process in detail.

The various stages of moulding:
The gelcoat, the protective boat “varnish”
What is the gelcoat?
It’s a polyester resin base in liquid form. There are several, pigmented to obtain the colour in accordance with our customers’ choice. It’s applied in the hull mould. Then the laid-up fabrics are applied to it.

What is its purpose?
It is used to ensure watertightness and gives a composite part its visible surface’s shiny finish; it enhances the visual appeal.

How is it applied?
Using a special spraying machine; cross-lapped coats are applied to attain a thickness between 0.6 and 0.8 mm, which is checked with a small tool called a wet film thickness gauge.

The lay-up, for optimised, reinforced and reliable structures
What does the layup consist of?
The layup is the application of the various layers of glass fibre and core materials constituting the scantlings of a composite part. The various layers are the first skin (also called moulding skin), the sandwich core, the reinforced areas, and the second skin.

Infusion, a guarantee of reliability and optimised weight
What is the infusion process?
It consists of the mould being placed under vacuum using a sheet, followed by impregnation of the laid-up fabric. The resin is drawn in by the vacuum created in the mould.

Which parts of the boat are infused?
All parts are infused.
What are the benefits?
By means of this process, we have better control over the amount of resin required for the infusion, the reproducibility of the moulded parts, the ability to produce large parts and improved working conditions for our operators.

Finally, what is the most problematic stage of the moulding? And why?
There’s more than one to ensure the compliance of parts such as those of the SEVENTY 7. They include the preparation of the mould prior to gelcoating, the quality of the moulding skin (resin and glass fibre) for the boat’s ultimate finish, the quality of layup and infusion, not forgetting the structure to ensure the robustness of the whole. In fact, every step is critical.

Do you have anything to add?
For my team and myself, moulding the SEVENTY 7 was a real challenge, one that we are proud to have overcome through the commitment, professionalism and motivation of all involved.

The SEVENTY 7 hull mould layup in figures:
Hull surface area: 200 m²
Gelcoat application time: 4 hours non-stop. In fact, this operation must be done in one go. It’s done at night, for supply to the production team in the morning.
Layup fabric application time: 3 weeks are required, employing 7 operators.
Time required for infusion: 2½ hours.

Laurent Fortinon
Moulding workshops manager
In 1999, he arrived at Lagoon as a moulding operator and he became a technician.
Then he was progressing as team manager on one-off activity and the last Lagoon 67.

Laurent coordinates the moulding teams (some thirty people) to ensure the successful execution of all projects in accordance with the production schedule. He acts as an intermediary between the production teams and support services (scheduling, design department, methods, logistics, etc.). There is a technician for each part to support him on the shopfloor. The goal is to produce quality parts on time, while safeguarding assets and people.